O O O O O / / / OH HO/ / / OH / / / // ==> ==> <== <== / / / / / / / // / C C C / / / C6H4.COOH C6H4 O C6H4.COOH / CO

This theory brings the property of fluorescence into relation with that of colour; the forms which cause fluorescence being the coloured modifications: ortho-quinonoid in the case of acridine, para-quinonoid in the case of fluorescein. H. Kauffmann (Ber., 1900, 33, p. 1731; 1904, 35, p. 294; 1905, 38, p. 789; Ann., 1906, 344, p. 30) suggested that the property is due to the presence of at least two groups. The first group, named the "luminophore," is such that when excited by suitable aetherial vibrations emits radiant energy; the other, named the "fluorogen," acts with the luminophore in some way or other to cause the fluorescence. This theory explains the fluorescence of anthranilic acid (o-aminobenzoic acid), by regarding the aniline residue as the luminophore, and the carboxyl group as the fluorogen, since, apparently, the introduction of the latter into the non-fluorescent aniline molecule involves the production of a fluorescent substance. Although the theories of Meyer and Hewitt do not explain (in their present form) the behaviour of anthranilic acid, yet Hewitt has shown that his theory goes far to explain the fluorescence of substances in which a double symmetrical tautomerism is possible. This tautomerism may be of a twofold nature:—(1) it may involve the mere oscillation of linkages, as in acridine; or (2) it may involve the oscillation of atoms, as in fluorescein. A theory of a physical nature, based primarily upon Sir J.J. Thomson's theory of corpuscles, has been proposed by J. de Kowalski (Compt. rend. 1907, 144, p. 266). We may notice that ethyl oxalosuccinonitrile is the first case of a fluorescent aliphatic compound (see W. Wislicenus and P. Berg, Ber., 1908, 41, p. 3757).

Capillarity and Surface Tension.—Reference should be made to the article CAPILLARY ACTION for the general discussion of this phenomenon of liquids. It is there shown that the surface tension of a liquid may be calculated from its rise in a capillary tube by the formula [gamma] = 1/2rhs, where [gamma] is the surface tension per square centimetre, r the radius of the tube, h the height of the liquid column, and s the difference between the densities of the liquid and its vapour. At the critical point liquid and vapour become identical, and, consequently, as was pointed out by Frankenheim in 1841, the surface tension is zero at the critical temperature.

Relation to molecular weight.

Mendeleeff endeavoured to obtain a connexion between surface energy and constitution; more successful were the investigations of Schiff, who found that the "molecular surface tension," which he defined as the surface tension divided by the molecular weight, is constant for isomers, and that two atoms of hydrogen were equal to one of carbon, three to one of oxygen, and seven to one of chlorine; but these ratios were by no means constant, and afforded practically no criteria as to the molecular weight of any substance.

In 1886 R. Eotvos (Wied. Ann. 27, p. 452), assuming that two liquids may be compared when the ratios of the volumes of the liquids to the volumes of the saturated vapours are the same, deduced that [gamma]V^{2/3} (where [gamma] is the surface tension, and V the molecular volume of the liquid) causes all liquids to have the same temperature coefficients. This theorem was investigated by Sir W. Ramsay and J. Shields (Journ. Chem. Soc. 63, p. 1089; 65, p. 167), whose results have thrown considerable light on the subject of the molecular complexity of liquids. Ramsay and Shields suggested that there exists an equation for the surface energy of liquids, analogous to the volume-energy equation of gases, PV = RT. The relation they suspected to be of the form [gamma]S = KT, where K is a constant analogous to R, and S the surface containing one gramme-molecule, [gamma] and T being the surface tension and temperature respectively. Obviously equimolecular surfaces are given by (Mv)^{2/3}, where M is the molecular weight of the substance, for equimolecular volumes are Mv, and corresponding surfaces the two-thirds power of this. Hence S may be replaced by (Mv)^{2/3}. Ramsay and Shields found from investigations of the temperature coefficient of the surface energy that T in the equation [gamma](Mv)^{2/3} = KT must be counted downwards from the critical temperature T less about 6 deg. Their surface energy equation therefore assumes the form [gamma](Mv)^{2/3} = K([tau] - 6 deg.). Now the value of K, [gamma] being measured in dynes and M being the molecular weight of the substance as a gas, is in general 2.121; this value is never exceeded, but in many cases it is less. This diminution implies an association of molecules, the surface containing fewer molecules than it is supposed to. Suppose the coefficient of association be n, i.e. n is the mean number of molecules which associate to form one molecule, then by the normal equation we have [gamma](Mnv)^{2/3} = 2.121([tau] - 6 deg.); if the calculated constant be K1, then we have also [gamma](Mv)^{2/3} = K1([tau]-6 deg.). By division we obtain n^{2/3} = 2.121/K1, or n = (2.121/K1)^{3/2} the coefficient of association being thus determined.

The apparatus devised by Ramsay and Shields consisted of a capillary tube, on one end of which was blown a bulb provided with a minute hole. Attached to the bulb was a glass rod and then a tube containing iron wire. This tube was placed in an outer tube containing the liquid to be experimented with; the liquid is raised to its boiling-point, and then hermetically sealed. The whole is enclosed in a jacket connected with a boiler containing a liquid, the vapour of which serves to keep the inner tube at any desired temperature. The capillary tube can be raised or lowered at will by running a magnet outside the tube, and the heights of the columns are measured by a cathetometer or micrometer microscope.

Normal values of K were given by nitrogen peroxide, N2O4, sulphur chloride, S2Cl2, silicon tetrachloride, SiCl4, phosphorus chloride, PCl3, phosphoryl chloride, POCl3, nickel carbonyl, Ni(CO)4, carbon disulphide, benzene, pyridine, ether, methyl propyl ketone; association characterized many hydroxylic compounds: for ethyl alcohol the factor of association was 2.74-2-43, for n-propyl alcohol 2.86-2.72, acetic acid 3.62-2.77, acetone 1.26, water 3.81-2.32; phenol, nitric acid, sulphuric acid, nitroethane, and propionitril, also exhibit association.

Crystalline Form and Composition.

The development of the theory of crystal structure, and the fundamental principles on which is based the classification of crystal forms, are treated in the article CRYSTALLOGRAPHY; in the same place will be found an account of the doctrine of isomorphism, polymorphism and morphotropy. Here we shall treat the latter subjects in more detail, viewed from the standpoint of the chemist. Isomorphism may be defined as the existence of two or more different substances in the same crystal form and structure, polymorphism as the existence of the same substance in two or more crystal modifications, and morphotropy (after P. von Groth) as the change in crystal form due to alterations in the molecule of closely (chemically) related substances. In order to permit a comparison of crystal forms, from which we hope to gain an insight into the prevailing molecular conditions, it is necessary that some unit of crystal dimensions must be chosen. A crystal may be regarded as built up of primitive parallelepipeda, the edges of which are in the ratio of the crystallographic axes, and the angles the axial angles of the crystals. To reduce these figures to a common standard, so that the volumes shall contain equal numbers of molecules, the notion of molecular volumes is introduced, the arbitrary values of the crystallographic axes (a, b, c) being replaced by the topic parameters[18] ([chi],[psi],[omega]), which are such that, combined with the axial angles, they enclose volumes which contain equal numbers of molecules. The actual values of the topic parameters can then readily be expressed in terms of the elements of the crystals (the axial ratios and angles), the density, and the molecular weight (see Groth, Physikalische Krystallographie, or Chemical Crystallography).

Polymorphism.—On the theory that crystal form and structure are the result of the equilibrium between the atoms and molecules composing the crystals, it is probable, a priori, that the same substance may possess different equilibrium configurations of sufficient stability, under favourable conditions, to form different crystal structures. Broadly this phenomenon is termed polymorphism; however, it is necessary to examine closely the diverse crystal modifications in order to determine whether they are really of different symmetry, or whether twinning has occasioned the apparent difference. In the article CRYSTALLOGRAPHY the nature and behaviour of twinned crystals receives full treatment; here it is sufficient to say that when the planes and axes of twinning are planes and axes of symmetry, a twin would exhibit higher symmetry (but remain in the same crystal system) than the primary crystal; and, also, if a crystal approximates in its axial constants to a higher system, mimetic twinning would increase the approximation, and the crystal would be pseudo-symmetric.

In general, polysymmetric and polymorphous modifications suffer transformation when submitted to variations in either temperature or pressure, or both. The criterion whether a pseudo-symmetric form is a true polymorph or not consists in the determination of the scalar properties (e.g. density, specific heat, &c.) of the original and the resulting modification, a change being in general recorded only when polymorphism exists. Change of temperature usually suffices to determine this, though in certain cases a variation in pressure is necessary; for instance, sodium magnesium uranyl acetate, NaMg(UO2)3(C2H3O2)9.9H2O shows no change in density unless the observations are conducted under a considerable pressure. Although many pseudo-symmetric twins are transformable into the simpler form, yet, in some cases, a true polymorph results, the change being indicated, as before, by alterations in scalar (as well as vector) properties.

For example, boracite forms pseudo-cubic crystals which become truly cubic at 265 deg., with a distinct change in density; leucite behaves similarly at about 560 deg.. Again, the pyroxenes, RSiO3 (R = Fe, Mg, Mn, &c.), assume the forms (1) monoclinic, sometimes twinned so as to become pseudo-rhombic; (2) rhombic, resulting from the pseudo-rhombic structure of (1) becoming ultramicroscopic; and (3) triclinic, distinctly different from (1) and (2); (1) and (2) are polysymmetric modifications, while (3) and the pair (1) and (2) are polymorphs.

While polysymmetry is solely conditioned by the manner in which the mimetic twin is built up from the single crystals, there being no change in the scalar properties, and the vector properties being calculable from the nature of the twinning, in the case of polymorphism entirely different structures present themselves, both scalar and vector properties being altered; and, in the present state of our knowledge, it is impossible to foretell the characters of a polymorphous modification. We may conclude that in polymorphs the substance occurs in different phases (or molecular aggregations), and the equilibrium between these phases follows definite laws, being dependent upon temperature and pressure, and amenable to thermodynamic treatment (cf. CHEMICAL ACTION and ENERGETICS). The transformation of polymorphs presents certain analogies to the solidification of a liquid. Liquids may be cooled below their freezing-point without solidification, the metastable (after W. Ostwald) form so obtained being immediately solidified on the introduction of a particle of the solid modification; and supersaturated solutions behave in a similar manner. At the same time there may be conditions of temperature and pressure at which polymorphs may exist side by side.

The above may be illustrated by considering the equilibrium between rhombic and monoclinic sulphur. The former, which is deposited from solutions, is transformed into monoclinic sulphur at about 96 deg., but with great care it is possible to overheat it and even to fuse it (at 113.5 deg.) without effecting the transformation. Monoclinic sulphur, obtained by crystallizing fused sulphur, melts at 119.5 deg., and admits of undercooling even to ordinary temperatures, but contact with a fragment of the rhombic modification spontaneously brings about the transformation. From Reicher's determinations, the exact transition point is 95.6 deg.; it rises with increasing pressure about 0.05 deg. for one atmosphere; the density of the rhombic form is greater than that of the monoclinic. The equilibria of these modifications may be readily represented on a pressure-temperature diagram. If OT, OP (fig. 6), be the axes of temperature and pressure, and A corresponds to the transition point (95.6 deg.) of rhombic sulphur, we may follow out the line AB which shows the elevation of the transition point with increasing pressure. The overheating curve of rhombic sulphur extends along the curve AC, where C is the melting-point of monoclinic sulphur. The line BC, representing the equilibrium between monoclinic and liquid sulphur, is thermodynamically calculable; the point B is found to correspond to 131 deg. and 400 atmospheres. From B the curve of equilibrium (BD) between rhombic and liquid sulphur proceeds; and from C (along CE) the curve of equilibrium between liquid sulphur and sulphur vapour. Of especial interest is the curve BD: along this line liquid and rhombic sulphur are in equilibrium, which means that at above 131 deg. and 400 atmospheres the rhombic (and not the monoclinic) variety would separate from liquid sulphur.

P D B / / Liquid / Rhombic / / E / - / Monoclinic - / - C / - /A / Vapour / / + O T FIG. 6.

Mercuric iodide also exhibits dimorphism. When precipitated from solutions it forms red tetragonal crystals, which, on careful heating, give a yellow rhombic form, also obtained by crystallization from the fused substance, or by sublimation. The transition point is 126.3 deg. (W. Schwarz, Zeit. f. Kryst. 25, p. 613), but both modifications may exist in metastable forms at higher and lower temperatures respectively; the rhombic form may be cooled down to ordinary temperature without changing, the transformation, however, being readily induced by a trace of the red modification, or by friction. The density and specific heat of the tetragonal form are greater than those of the yellow.

Hexachlorethane is trimorphous, forming rhombic, triclinic and cubic crystals; the successive changes occur at about 44 deg. and 71 deg., and are attended by a decrease in density.

Tetramorphism is exhibited by ammonium nitrate. According to O. Lehmann it melts at 168 deg. (or at a slightly lower temperature in its water of crystallization) and on cooling forms optically isotropic crystals; at 125.6 deg. the mass becomes doubly refracting, and from a solution rhombohedral (optically uniaxial) crystals are deposited; by further cooling acicular rhombic crystals are produced at 82.8 deg., and at 32.4 deg. other rhombic forms are obtained, identical with the product obtained by crystallizing at ordinary temperatures. The reverse series of transformations occurs when this final modification is heated. M. Bellati and R. Romanese (Zeit. f. Kryst. 14, p. 78) determined the densities and specific heats of these modifications. The first and third transformations (reckoned in order with increasing temperature of the transition point) are attended by an increase in volume, the second with a contraction; the solubility follows the same direction, increasing up to 82.8 deg., then diminishing up to 125.6 deg., and then increasing from this temperature upwards.

The physical conditions under which polymorphous modifications are prepared control the form which the substance assumes. We have already seen that temperature and pressure exercise considerable influence in this direction. In the case of separation from solutions, either by crystallization or by precipitation by double decomposition, the temperature, the concentration of the solution, and the presence of other ions may modify the form obtained. In the case of sodium dihydrogen phosphate, NaH2PO4.H2O, a stable rhombic form is obtained from warm solutions, while a different, unstable, rhombic form is obtained from cold solutions. Calcium carbonate separates as hexagonal calcite from cold solutions (below 30 deg.), and as rhombic aragonite from solutions at higher temperatures; lead and strontium carbonates, however, induce the separation of aragonite at lower temperatures. From supersaturated solutions the form unstable at the temperature of the experiment is, as a rule, separated, especially on the introduction of a crystal of the unstable form; and, in some cases, similar inoculation of the fused substance is attended by the same result. Different modifications may separate and exist side by side at one and the same time from a solution; e.g. telluric acid forms cubic and monoclinic crystals from a hot nitric acid solution, and ammonium fluosilicate gives cubic and hexagonal forms from aqueous solutions between 6 deg. and 13 deg.

A comparison of the transformation of polymorphs leads to a twofold classification: (1) polymorphs directly convertible in a reversible manner—termed "enantiotropic" by O. Lehmann and (2) polymorphs in which the transformation proceeds in one direction only—termed "monotropic." In the first class are included sulphur and ammonium nitrate; monotropy is exhibited by aragonite and calcite.

It is doubtful indeed whether any general conclusions can yet be drawn as to the relations between crystal structure and scalar properties and the relative stability of polymorphs. As a general rule the modification stable at higher temperatures possesses a lower density; but this is by no means always the case, since the converse is true for antimonious and arsenious oxides, silver iodide and some other substances. Attempts to connect a change of symmetry with stability show equally a lack of generality. It is remarkable that a great many polymorphous substances assume more symmetrical forms at higher temperatures, and a possible explanation of the increase in density of such compounds as silver iodide, &c., may be sought for in the theory that the formation of a more symmetrical configuration would involve a drawing together of the molecules, and consequently an increase in density. The insufficiency of this argument, however, is shown by the data for arsenious and antimonious oxides, and also for the polymorphs of calcium carbonate, the more symmetrical polymorphs having a lower density.

Morphotropy.—Many instances have been recorded where substitution has effected a deformation in one particular direction, the crystals of homologous compounds often exhibiting the same angles between faces situated in certain zones. The observations of Slavik (Zeit. f. Kryst., 1902, 36, p. 268) on ammonium and the quaternary ammonium iodides, of J.A. Le Bel and A. Ries (Zeit. f. Kryst., 1902, 1904, et seq.) on the substituted ammonium chlorplatinates, and of G. Mez (ibid., 1901, 35, p. 242) on substituted ureas, illustrate this point.

Ammonium iodide assumes cubic forms with perfect cubic cleavage; tetramethyl ammonium iodide is tetragonal with perfect cleavages parallel to {100} and {001}—a difference due to the lengthening of the a axes; tetraethyl ammonium iodide also assumes tetragonal forms, but does not exhibit the cleavage of the tetramethyl compound; while tetrapropyl ammonium iodide crystallizes in rhombic form. The equivalent volumes and topic parameters are tabulated:

- - NH4I. NMe4I. NEt4I. NPr4I. - - V 57.51 108.70 162.91 235.95 [chi] 3.860 5.319 6.648 6.093 [psi] 3.860 5.319 6.648 7.851 [omega] 3.860 3.842 3.686 4.933 - -

From these figures it is obvious that the first three compounds form a morphotropic series; the equivalent volumes exhibit a regular progression; the values of [chi] and [psi], corresponding to the a axes, are regularly increased, while the value of [omega], corresponding to the c axis, remains practically unchanged. This points to the conclusion that substitution has been effected in one of the cube faces. We may therefore regard the nitrogen atoms as occupying the centres of a cubic space lattice composed of iodine atoms, between which the hydrogen atoms are distributed on the tetrahedron face normals. Coplanar substitution in four hydrogen atoms would involve the pushing apart of the iodine atoms in four horizontal directions. The magnitude of this separation would obviously depend on the magnitude of the substituent group, which may be so large (in this case propyl is sufficient) as to cause unequal horizontal deformation and at the same time a change in the vertical direction.

The measure of the loss of symmetry associated with the introduction of alkyl groups depends upon the relative magnitudes of the substituent group and the rest of the molecule; and the larger the molecule, the less would be the morphotropic effect of any particular substituent. The mere retention of the same crystal form by homologous substances is not a sufficient reason for denying a morphotropic effect to the substituent group; for, in the case of certain substances crystallizing in the cubic system, although the crystal form remains unaltered, yet the structures vary. When both the crystal form and structure are retained, the substances are said to be isomorphous.

Other substituent groups exercise morphotropic effects similar to those exhibited by the alkyl radicles; investigations have been made on halogen-, hydroxy-, and nitro-derivatives of benzene and substituted benzenes. To Jaeger is due the determination of the topic parameters of certain haloid-derivatives, and, while showing that the morphotropic effects closely resemble those occasioned by methyl, he established the important fact that, in general, the crystal form depended upon the orientation of the substituents in the benzene complex.

Benzoic acid is pseudo-tetragonal, the principal axis being remarkably long; there is no cleavage at right angles to this axis. Direct nitration gives (principally) m-nitrobenzoic acid, also pseudo-tetragonal with a much shorter principal axis. From this two chlornitrobenzoic acids [COOH.NO2.Cl = 1.3.6 and 1.3.4] may be obtained. These are also pseudotetragonal; the (1.3.6) acid has nearly the same values of [chi] and [psi] as benzoic acid, but [omega] is increased; compared with m-nitrobenzoic acid, [chi] and [psi] have been diminished, whereas [omega] is much increased; the (1.3.4) acid is more closely related to m-nitrobenzoic acid, [chi] and [psi] being increased, [omega] diminished. The results obtained for the (1.2) and (1.4) chlorbenzoic acids also illustrate the dependence of crystal form and structure on the orientation of the molecule.

The hydroxyl group also resembles the methyl group in its morphotropic effects, producing, in many cases, no change in symmetry but a dimensional increase in one direction. This holds for benzene and phenol, and is supported by the observations of Gossner on [1.3.5] trinitrobenzene and picric acid (1.3.5-trinitro, 2 oxybenzene); these last two substances assume rhombic forms, and picric acid differs from trinitrobenzene in having [omega] considerably greater, with [chi] and [psi] slightly less. A similar change, in one direction only, characterizes benzoic acid and salicylic acid.

The nitro group behaves very similarly to the hydroxyl group. The effect of varying the position of the nitro group in the molecule is well marked, and conclusions may be drawn as to the orientation of the groups from a knowledge of the crystal form; a change in the symmetry of the chemical molecule being often attended by a loss in the symmetry of the crystal.

It may be generally concluded that the substitution of alkyl, nitro, hydroxyl, and haloid groups for hydrogen in a molecule occasions a deformation of crystal structure in one definite direction, hence permitting inferences as to the configuration of the atoms composing the crystal; while the nature and degree of the alteration depends (1) upon the crystal structure of the unsubstituted compound; (2) on the nature of the substituting radicle; (3) on the complexity of the substituted molecule; and (4) on the orientation of the substitution derivative.

Isomorphism.—It has been shown that certain elements and groups exercise morphotropic effects when substituted in a compound; it may happen that the effects due to two or more groups are nearly equivalent, and consequently the resulting crystal forms are nearly identical. This phenomenon was first noticed in 1822 by E. Mitscherlich, in the case of the acid phosphate and acid arsenate of potassium, KH2P(As)O4, who adopted the term isomorphism, and regarded phosphorus and arsenic as isomorphously related elements. Other isomorphously related elements and groups were soon perceived, and it has been shown that elements so related are also related chemically.

Tutton's investigations of the morphotropic effects of the metals potassium, rubidium and caesium, in combination with the acid radicals of sulphuric and selenic acids, showed that the replacement of potassium by rubidium, and this metal in turn by caesium, was accompanied by progressive changes in both physical and crystallographical properties, such that the rubidium salt was always intermediate between the salts of potassium and caesium (see table; the space unit is taken as a pseudo-hexagonal prism). This fact finds a parallel in the atomic weights of these metals.

- - - - - V [chi] [psi] [omega] - - - - - K2SO4 69.42 4.464 4.491 4.997 Rb2SO4 73.36 4.634 4.664 5.237 Cs2SO4 83.64 4.846 4.885 5.519 - - - - - K2SeO4 71.71 4.636 4.662 5.118 Rb2SeO4 79.95 4.785 4.826 5.346 Cs2SeO4 91.16 4.987 5.035 5.697 - - - - -

By taking appropriate differences the following facts will be observed: (1) the replacement of potassium by rubidium occasions an increase in the equivalent volumes by about eight units, and of rubidium by caesium by about eleven units; (2) replacement in the same order is attended by a general increase in the three topic parameters, a greater increase being met with in the replacement of rubidium by caesium; (3) the parameters [chi] and [psi] are about equally increased, while the increase in [omega] is always the greatest. Now consider the effect of replacing sulphur by selenium. It will be seen that (1) the increase in equivalent volume is about 6.6; (2) all the topic parameters are increased; (3) the greatest increase is effected in the parameters [chi] and [psi], which are equally lengthened.

These observations admit of ready explanation in the following manner. The ordinary structural formula of potassium sulphate is

O K O S O K. O

If the crystal structure be regarded as composed of three interpenetrating point systems, one consisting of sulphur atoms, the second of four times as many oxygen atoms, and the third of twice as many potassium atoms, the systems being so arranged that the sulphur system is always centrally situated with respect to the other two, and the potassium system so that it would affect the vertical axis, then it is obvious that the replacement of potassium by an element of greater atomic weight would specially increase the length of [omega] (corresponding to the vertical axis), and cause a smaller increase in the horizontal parameters [chi] and [psi]; moreover, the increments would advance with the atomic weight of the replacing metal. If, on the other hand, the sulphur system be replaced by a corresponding selenium system, an element of higher atomic weight, it would be expected that a slight increase would be observed in the vertical parameter, and a greater increase recorded equally in the horizontal parameters.

Muthmann (Zeit. f. Kryst., 1894), in his researches on the tetragonal potassium and ammonium dihydrogen phosphates and arsenates, found that the replacement of potassium by ammonium was attended by an increase of about six units in the molecular volume, and of phosphorus by arsenic by about 4.6 units. In the topic parameters the following changes were recorded: replacement of potassium by ammonium was attended by a considerable increase in [omega], [chi] and [psi] being equally, but only slightly, increased; replacement of phosphorus by arsenic was attended by a considerable increase, equally in [chi] and [psi], while [omega] suffered a smaller, but not inconsiderable, increase. It is thus seen that the ordinary plane representation of the structure of compounds possesses a higher significance than could have been suggested prior to crystallographical researches.

Identity, or approximate identity, of crystal form is not in itself sufficient to establish true isomorphism. If a substance deposits itself on the faces of a crystal of another substance of similar crystal form, the substances are probably isomorphous. Such parallel overgrowths, termed episomorphs, are very common among the potassium and sodium felspars; and K. von Hauer has investigated a number of cases in which salts exhibiting episomorphism have different colours, thereby clearly demonstrating this property of isomorphism. For example, episomorphs of white potash alum and violet chrome alum, of white magnesium sulphate and green nickel sulphate, and of many other pairs of salts, have been obtained. More useful is the property of isomorphous substances of forming mixed crystals, which are strictly isomorphous with their constituents, for all variations in composition. In such crystals each component plays its own part in determining the physical properties; in other words, any physical constant of a mixed crystal can be calculated as additively composed of the constants of the two components.





Fig. 7 represents the specific volumes of mixtures of ammonium and potassium sulphates; the ordinates representing specific volumes, and the abscissae the percentage composition of the mixture. Fig. 8 shows the variation of refractive index of mixed crystals of potash alum and thallium alum with variation in composition.

In these two instances the component crystals are miscible in all proportions; but this is by no means always the case. It may happen that the crystals do not form double salts, and are only miscible in certain proportions. Two cases then arise: (1) the properties may be expressed as linear functions of the composition, the terminal values being identical with those obtained for the individual components, and there being a break in the curve corresponding to the absence of mixed crystals; or (2) similar to (1) except that different values must be assigned to the terminal values in order to preserve collinearity. Fig. 9 illustrates the first case: the ordinates represent specific volumes, and the abscissae denote the composition of isomorphous mixtures of ammonium and potassium dihydrogen phosphates, which mutually take one another up to the extent of 20% to form homogeneous crystals. The second case is illustrated in fig. 10. Magnesium sulphate (orthorhombic) takes up ferrous sulphate (monoclinic) to the extent of 19%, forming isomorphous orthorhombic crystals; ferrous sulphate, on the other hand, takes up magnesium sulphate to the extent of 54% to form monoclinic crystals. By plotting the specific volumes of these mixed crystals as ordinates, it is found that they fall on two lines, the upper corresponding to the orthorhombic crystals, the lower to the monoclinic. From this we may conclude that these salts are isodimorphous: the upper line represents isomorphous crystals of stable orthorhombic magnesium sulphate and unstable orthorhombic ferrous sulphate, the lower line isomorphous crystals of stable monoclinic ferrous sulphate and unstable monoclinic magnesium sulphate.





An important distinction separates true mixed crystals and crystallized double salts, for in the latter the properties are not linear functions of the properties of the components; generally there is a contraction in volume, while the refractive indices and other physical properties do not, in general, obey the additive law.

Isomorphism is most clearly discerned between elements of analogous chemical properties; and from the wide generality of such observations attempts have been made to form a classification of elements based on isomorphous replacements. The following table shows where isomorphism may be generally expected. The elements are arranged in eleven series, and the series are subdivided (as indicated by semicolons) into groups; these groups exhibit partial isomorphism with the other groups of the same series (see W. Nernst, Theoretical Chemistry).

Series 1. Cl, Br, I, F; Mn (in permanganates). 2. S, Se; Te (in tellurides); Cr, Mn, Te (in the acids H2RO4); As, Sb (in the glances MR2). 3. As, Sb, Bi; Te (as an element); P, Vd (in salts); N, P (in organic bases). 4. K, Na, Cs, Rb, Li; Tl, Ag. 5. Ca, Ba, Sr, Pb; Fe, Zn, Mn, Mg; Ni, Co, Cu; Ce, La, Di, Er, Y, Ca; Cu, Hg, Pb; Cd, Be, In, Zn; Tl, Pb. 6. Al, Fe, Cr, Mn; Ce, U (in sesquioxides). 7. Cu, Ag (when monovalent); Au. 8. Pt, Ir, Pd, Rh, Ru, Os; Au, Fe, Ni; Sn, Te. 9. C, Si, Ti, Zr, Th, Sn; Fe, Ti. 10. Ta, Cb (Nb). 11. Mo, W, Cr.

For a detailed comparison of the isomorphous relations of the elements the reader is referred to P. von Groth, Chemical Crystallography. Reference may also be made to Ida Freund, The Study of Chemical Composition; and to the Annual Reports of the Chemical Society for 1908, p. 258.

BIBLIOGRAPHY.—History: F. Hoefer, Histoire de la chimie (2nd ed., 1866-1869); Hermann Kopp, Geschichte der Chemie (1869), Entwickelung der Chemie in d. neueren Zeit (1871-1874); E. von Meyer, Geschichte der Chemie (3rd ed., 1905, Eng. trans.); A. Ladenburg, Entwickelungsgeschichte der Chemie (4th ed., 1907); A. Stange, Die Zeitalter der Chemie (1908). Reference may also be made to M.M. Pattison Muir, History of Chemical Theories and Laws (1907); Ida Freund, Study of Chemical Composition (1904); T.E. Thorpe, Essays in Historical Chemistry (2nd ed., 1902). See also the article ALCHEMY.

Principles and Physical.—W. Ostwald, Principles of Inorganic Chemistry (3rd Eng. ed., 1908), Outlines of General Chemistry, Lehrbuch der allgemeinen Chemie; W. Nernst, Theoretische Chemie (4th ed., 1907, Eng. trans.); J.H. van't Hoff, Lectures on Theoretical and Physical Chemistry; J. Walker, Introduction to Physical Chemistry (4th ed., 1907); H.C. Jones, Outlines of Physical Chemistry (1903); D. Mendeleeff, Principles of Chemistry (3rd ed., 1905).

Inorganic.—Roscoe and Schorlemmer, Inorganic Chemistry (3rd ed., Non-metals, 1905; Metals, 1907); R. Abegg, Handbuch der anorganischen Chemie; Gmelin-Kraut, Handbuch der anorganischen Chemie; O. Dammer, Handbuch der anorganischen Chemie; H. Moissan, Chimie minerale.

Organic.—F. Beilstein, Handbuch der organischen Chemie; M.M. Richter, Lexikon der Kohlenstoffverbindungen (these are primarily works of reference); V. Meyer and P.H. Jacobson, Lehrbuch der organischen Chemie; Richter-Anschutz, Organische Chemie (11th ed., vol. i., 1909, Eng. trans.); G.K. Schmidt, Kurzes Lehrbuch der organischen Chemie; A. Bernthsen, Organische Chemie (Eng. trans.). Practical methods are treated in Lassar-Cohn, Arbeitsmethoden fur organisch-chemische Laboratorien (4th ed., 1906-1907). Select chapters are treated in A. Lachmann, Spirit of Organic Chemistry; J.B. Cohen, Organic Chemistry (1908); A.W. Stewart, Recent Advances in Organic Chemistry (1908); and in a series of pamphlets issued since 1896 with the title Sammlung chemischer und chemisch-technischer Vortrage.

Analytical.—For Blowpipe Analysis: C.F. Plattner, Probirkunst mit dem Lothrohr. For General Analysis: C.R. Fresenius, Qualitative and Quantitative Analysis, Eng. trans, by C.E. Groves (Qualitative, 1887) and A.I. Cohn (Quantitative, 1903); F.P. Treadwell, Kurzes Lehrbuch der analytischen Chemie (1905); F. Julian, Textbook of Quantitative Chemical Analysis (1904); A. Classen, Ausgewahlte Methoden der analytischen Chemie (1901-1903); W. Crookes, Select Methods in Chemical Analysis (1894). Volumetric Analysis: F. Sutton, Systematic Handbook of Volumetric Analysis (1904); F. Mohr, Lehrbuch der chemisch-analytischen Titrirmethode (1896). Organic Analysis: Hans Meyer, Analyse und Konstitutionsermittlung organischer Verbindungen (1909); Wilhelm Vaubel, Die physikalischen und chemischen Methoden der quantitativen Bestimmung organischer Verbindungen. For the historical development of the proximate analysis of organic compounds see M.E.H. Dennstedt, Die Entwickelung der organischen Elementaranalyse (1899).

Encyclopaedias.—The early dictionaries of Muspratt and Watts are out of date; there is a later edition of the latter by H.F. Morley and M.M.P. Muir. A. Ladenburg, Handworterbuch der Chemie, A. Wurtz, Dictionnaire de chimie, and F. Selmi, Enciclopedia di chimica, are more valuable; the latter two are kept up to date by annual supplements. (C. E.*)

FOOTNOTES:

[1] The more notable chemists of this period were Turquet de Mayerne (1573-1665), a physician of Paris, who rejected the Galenian doctrines and accepted the exaggerations of Paracelsus; Andreas Libavius (d. 1616), chiefly famous for his Opera Omnia Medicochymica (1595); Jean Baptiste van Helmont (1577-1644), celebrated for his researches on gases; F. de la Boe Sylvius (1614-1672), who regarded medicine as applied chemistry; and Otto Tachenius, who elucidated the nature of salts.

[2] This dictum was questioned by the researches of H. Landolt, A. Heydweiller and others. In a series of 75 reactions it was found that in 61 there was apparently a diminution in weight, but in 1908, after a most careful repetition and making allowance for all experimental errors, Landolt concluded that no change occurred (see ELEMENT).

[3] The theory of Berthollet was essentially mechanical, and he attempted to prove that the course of a reaction depended not on affinities alone but also on the masses of the reacting components. In this respect his hypothesis has much in common with the "law of mass-action" developed at a much later date by the Swedish chemists Guldberg and Waage, and the American, Willard Gibbs (see CHEMICAL ACTION). In his classical thesis Berthollet vigorously attacked the results deduced by Bergman, who had followed in his table of elective attractions the path traversed by Stahl and S. F. Geoffroy.

[4] Dalton's atomic theory is treated in more detail in the article ATOM.

[5] Berzelius, however, appreciated the necessity of differentiating the atom and the molecule, and even urged Dalton to amend his doctrine, but without success.

[6] The following symbols were also used by Bergman:—



which represented zinc, manganese, cobalt, bismuth, nickel, arsenic, platinum, water, alcohol, phlogiston.

[7] The following are the symbols employed by Dalton:—



which represent in order, hydrogen, nitrogen, carbon, oxygen, phosphorus, sulphur, magnesia, lime, soda, potash, strontia, baryta, mercury; iron, zinc, copper, lead, silver, platinum, and gold were represented by circles enclosing the initial letter of the element.

[8] Approximate values of the atomic weights are employed here.

[9] The definite distinction between potash and soda was first established by Duhamel de Monceau (1700-1781).

[10] The reader is specially referred to the articles ALIZARIN; INDIGO; PURIN and TERPENES for illustrations of the manner in which chemists have artificially prepared important animal and vegetable products.

[11] These observations were generalized by J.B. Dumas and Polydore Boullay (1806-1835) in their "etherin theory" (vide infra).

[12] This must not be confused with the modern acetyl, CH3.CO, which at that time was known as acetoxyl.

[13] It is now established that ortho compounds do exist in isomeric forms, instances being provided by chlor-, brom-, and amino-toluene, chlorphenol, and chloraniline; but arguments, e.g. E. Knoevenagel's theory of "motoisomerism," have been brought forward to cause these facts to support Kekule.

[14] Victor Meyer and G. Heyl (Ber., 1895, 28, p. 2776) attempted a solution from the following data. It is well known that di-ortho-substituted benzoic acids are esterified with difficulty. Two acids corresponding to the formula of Kekule and Claus are triphenyl acrylic acid, (C6H5)2C:C(COOH).C6H5, and triphenyl acetic acid, (C6H5)3C.COOH. Experiments showed that the second acid was much more difficult to esterify than the first, pointing to the conclusion that Claus' formula for benzene was more probable than Kekule's.

[15] H. Rose, Ausfuhrliches Handbuch der analytischen Chemie (1851).

[16] F. Wohler, Die Mineralanalyse in Beispielen (1861).

[17] For the connexion between valency and volume, see VALENCY.

[18] This was done simultaneously in 1894 by W. Muthmann and A. E. H. Tutton, the latter receiving the idea from F. Becke (see Journ. Chem. Soc., 1896, 69, p. 507; 1905, 87, p. 1183).



CHEMNITZ (or KEMNITZ), MARTIN (1522-1586), German Lutheran theologian, third son of Paul Kemnitz, a cloth-worker of noble extraction, was born at Treuenbrietzen, Brandenburg, on the 9th of November 1522. Left an orphan at the age of eleven, he worked for a time at his father's trade. A relative at Magdeburg put him to school there (1539-1542). Having made a little money by teaching, he went (1543) to the university of Frankfort-on-Oder; thence (1545) to that of Wittenberg. Here he heard Luther preach, but was more attracted by Melanchthon, who interested him in mathematics and astrology. Melanchthon gave him (1547) an introduction to his son-in-law, Georg Sabinus, at Konigsberg, where he was tutor to some Polish youths, and rector (1548) of the Kneiphof school. He practised astrology; this recommended him to Duke Albert of Prussia, who made him his librarian (1550). He then turned to Biblical, patristic and kindred studies. His powers were first brought out in controversy with Osiander on justification by faith. Osiander, maintaining the infusion of Christ's righteousness into the believer, impugned the Lutheran doctrine of imputation; Chemnitz defended it with striking ability. As Duke Albert sided with Osiander, Chemnitz resigned the librarianship. Returning (1553) to Wittenberg, he lectured on Melanchthon's Loci Communes, his lectures forming the basis of his own Loci Theologici (published posthumously, 1591), which constitute probably the best exposition of Lutheran theology as formulated and modified by Melanchthon. His lectures were thronged, and a university career of great influence lay before him, when he accepted a call to become coadjutor at Brunswick to the superintendent, Joachim Morlin, who had known him at Konigsberg. He removed to Brunswick on the 15th of December 1554, and there spent the remainder of his life, refusing subsequent offers of important offices from various Protestant princes of Germany. Zealous in the duties of his pastoral charge, he took a leading part in theological controversy. His personal influence, at a critical period, did much to secure strictness of doctrine and compactness of organization in the Lutheran Church. Against Crypto-Calvinists he upheld the Lutheran view of the eucharist in his Repetitio sanae doctrinae de Vera Praesentia (1560; in German, 1561). To check the reaction towards the old religion he wrote several works of great power, especially his Theologiae Jesuitarum praecipua capita (1562), an incisive attack on the principles of the society, and the Examen concilii Tridentini (four parts, 1565-66-72-73), his greatest work. His Corpus doctrinae Prutenicum (1567), drawn up in conjunction with Morlin, at once acquired great authority. In the year of its publication he became superintendent of Brunswick, and in effect the director of his church throughout Lower Saxony. His tact was equal to his learning. In conjunction with Andrea and Selnecker he induced the Lutherans of Saxony and Swabia to adopt the Formula Concordiae and so become one body. Against lax views of Socinian tendency he directed his able treatise De duabus naluris in Christo (1570). Resigning office in infirm health (1584) he survived till the 8th of April 1586.

Lives of Chemnitz are numerous, e.g. by T. Gasmerus (1588), T. Pressel (1862), C.G.H. Lentz (1866), H. Hachfeld (1867), H. Schmid in J.J. Herzog's Realencyklopadie (1878), T. Kunze in A. Hauck's Realencyklop. fur prot. Theol. und Kirche (1897); that by Hausle, in I. Goschler's Dict. encyclopedique de la theol. cath. (1858), gives a Roman Catholic view. (A. Go.*)



CHEMNITZ, a town of Germany, in the kingdom of Saxony, the capital of a governmental district, 50 m. W.S.W. of Dresden and 51 S.E. of Leipzig by rail. Pop. (1885) 110,817; (1895) 161,017; (1905) 244,405. It lies 950 ft. above the sea, in a fertile plain at the foot of the Erzgebirge, watered by the river Chemnitz, an affluent of the Mulde. It is the chief manufacturing town in the kingdom, ranks next to Dresden and Leipzig in point of population, and is one of the principal commercial and industrial centres of Germany. It is well provided with railway communication, being directly connected with Berlin and with the populous and thriving towns of the Erzgebirge and Voigtland. Chemnitz is in general well built, the enormous development of its industry and commerce having of late years led to the laying out of many fine streets and to the embellishing of the town with handsome buildings. The centre is occupied by the market square, with the handsome medieval Rathaus, now superseded for municipal business by a modern building in the Post-strasse. In this square are monuments to the emperor William I., Bismarck and Moltke. The old inner town is surrounded by pleasant promenades, occupying the site of the old fortifications, and it is beyond these that industrial Chemnitz lies, girdling the old town on all sides with a thick belt of streets and factories, and ramifying far into the country. Chemnitz has eleven Protestant churches, among them the ancient Gothic church of St James, with a fine porch, and the modern churches of St Peter, St Nicholas and St Mark. There are also a synagogue and chapels of various sects. The industry of Chemnitz has gained for the town the name of "Saxon Manchester." First in importance are its locomotive and engineering works, which give employment to some 20,000 hands in 90 factories. Next come its cotton-spinning, hosiery, textile and glove manufactures, in which a large trade is done with Great Britain and the United States. It is also the seat of considerable dyeworks, bleachworks, chemical and woollen factories, and produces leather and straps, cement, small vehicles, wire-woven goods, carpets, beer and bricks. The town is well provided with technical schools for training in the various industries, including commercial, public, economic and agricultural schools, and has a chamber of commerce. There are also industrial and historical museums, and collections of painting and natural history. The local communications are maintained by an excellent electric tramway system. To the northwest of the town is the Gothic church of a former Benedictine monastery, dating from 1514-1525, with a tower of 1897. Chemnitz is a favourite tourist centre for excursions into the Erzgebirge, the chain of mountains separating Saxony from Bohemia.

Chemnitz (Kaminizi) was originally a settlement of the Serbian Wends and became a market town in 1143. Its municipal constitution dates from the 14th century, and it soon became the most important industrial centre in the mark of Meissen. A monopoly of bleaching was granted to the town, and thus a considerable trade in woollen and linen yarns was attracted to Chemnitz; paper was made here, and in the 16th century the manufacture of cloth was very flourishing. In 1539 the Reformation was introduced, and in 1546 the Benedictine monastery, founded about 1136 by the emperor Lothair II. about 2 m. north of the town, was dissolved. During the Thirty Years' War Chemnitz was plundered by all parties and its trade was completely ruined, but at the beginning of the 18th century it had begun to recover. Further progress in this direction was made during the 19th century, especially after 1834 when Saxony joined the German Zollverein.

See Zollner, Geschichte der Fabrik- und Handelsstadt Chemnitz (1891); and Straumer, Die Fabrik- und Handelsstadt Chemnitz (1892).



CHEMOTAXIS (from the stem of "chemistry" and Gr. [Greek: taxis], arrangement), a biological term for the attraction exercised on living or growing organisms or their members by chemical substances; e.g. the attraction of the male cells of ferns or mosses by an organic acid or sugar-solution.



CHENAB (the Greek Acesines), one of the "Five rivers" of the Punjab, India. It rises in the snowy Himalayan ranges of Kashmir, enters British territory in the Sialkot district, and flows through the plains of the Punjab, forming the boundary between the Rechna and the Jech Doabs. Finally it joins the Jhelum at Trimmu.

The CHENAB COLONY, resulting from the great success of the Chenab Canal in irrigating the desert of the Bar, was formed out of the three adjacent districts of Gujranwala, Jhang, and Montgomery in 1892, and contained in 1901 a population of 791,861. It lies in the Rechna Doab between the Chenab and Ravi rivers in the north-east of the Jhang district, and is designed to include an irrigated area of 2-1/2 million acres. The Chenab Canal (opened 1887) is the largest and most profitable perennial canal in India. The principal town is Lyallpur, called after Sir J. Broad wood Lyall, lieutenant-governor of the Punjab 1887-1892, which gives its name to a district created in 1904.



CHENEDOLLE, CHARLES JULIEN LIOULT DE (1769-1833), French poet, was born at Vire (Calvados) on the 4th of November 1769. He early showed a vocation for poetry, but the outbreak of the Revolution temporarily diverted his energy. Emigrating in 1791, he fought two campaigns in the army of Conde, and eventually found his way to Hamburg, where he met Antoine de Rivarol, of whose brilliant conversation he has left an account. He also visited Mme de Stael in her retreat at Coppet. On his return to Paris in 1799 he met Chateaubriand and his sister Lucile (Mme de Caud), to whom he became deeply attached. After her death in 1804, Chenedolle returned to Normandy, where he married and became eventually inspector of the academy of Caen (1812-1832). With the exception of occasional visits to Paris, he spent the rest of his life in his native province. He died at the chateau de Coisel on the 2nd of December 1833. He published his Genie de l'Homme in 1807, and in 1820 his Etudes poetiques, which had the misfortune to appear shortly after the Meditations of Lamartine, so that the author did not receive the credit of their real originality. Chenedolle had many sympathies with the romanticists, and was a contributor to their organ, the Muse francaise. His other works include the Esprit de Rivarol (1808) in conjunction with F.J.M. Fayolle.

The works of Chenedolle were edited in 1864 by Sainte-Beuve, who drew portraits of him in his Chateaubriand et son groupe and in an article contributed to the Revue des deux mondes (June 1849). See also E. Helland, Etude biographique et litteraire sur Chenedolle (1857); Cazin, Notice sur Chenedolle (1869).



CHENERY, THOMAS (1826-1884), English scholar and editor of The Times, was born in 1826 at Barbados. He was educated at Eton and Caius College, Cambridge. Having been called to the bar, he went out to Constantinople as The Times correspondent just before the Crimean War, and it was under the influence there of Algernon Smythe (afterwards Lord Strangford) that he first turned to those philological studies in which he became eminent. After the war he returned to London and wrote regularly for The Times for many years, eventually succeeding Delane as editor in 1877. He was then an experienced publicist, particularly well versed in Oriental affairs, an indefatigable worker, with a rapid and comprehensive judgment, though he lacked Delane's intuition for public opinion. It was as an Orientalist, however, that he had meantime earned the highest reputation, his knowledge of Arabic and Hebrew being almost unrivalled and his gift for languages exceptional. In 1868 he was appointed Lord Almoner's professor of Arabic at Oxford, and retained his position until he became editor of The Times. He was one of the company of revisers of the Old Testament. He was secretary for some time to the Royal Asiatic Society, and published learned editions of the Arabic classic The Assemblies of Al-Hariri and of the Machberoth Ithiel. He died in London on the 11th of February 1884.



CHENG, TSCHENG or TSCHIANG (Ger. Scheng), an ancient Chinese wind instrument, a primitive organ, containing the principle of the free reed which found application in the accordion, concertina and harmonium. The cheng resembles a tea-pot filled with bamboo pipes of graduated lengths. It consists of a gourd or turned wooden receptacle acting as wind reservoir, in the side of which is inserted an insufflation tube curved like a swan's neck or the spout of a tea-pot. The cup-shaped reservoir is closed by means of a plate of horn pierced with seventeen round holes arranged round the edge in an unfinished circle, into which fit the bamboo pipes. The pipes are cylindrical as far as they are visible above the plate, but the lower end inserted in the wind reservoir is cut to the shape of a beak, somewhat like the mouthpiece of the clarinet, to receive the reed. The construction of the free reed is very simple: it consists of a thin plate of metal—gold according to the Jesuit missionary Joseph Amiot,[1] but brass in the specimens brought to Europe—of the thickness of ordinary paper. In this plate is cut a rectangular flap or tongue which remains fixed at one end, while at the other the tongue is filed so that, instead of closing the aperture, it passes freely through, vibrating as the air is forced through the pipe (see FREE-REED VIBRATOR). The metal plate is fastened with wax longitudinally across the diameter of the beak end of the pipe, a little layer of wax being applied also to the free end of the vibrating tongue for the purpose of tuning by adding weight and impetus. About half an inch above the horn plate a small round hole or stop is bored through the pipe, which speaks only when this hole is covered by the finger. A longitudinal aperture about an inch long cut in the upper end of the bamboo pipe serves to determine the length of the vibrating column of air proper to respond to the vibrations of the free reed. The length of the bamboo above this opening is purely ornamental, as are also four or five of the seventeen pipes which have no reeds and do not speak, being merely inserted for the purposes of symmetry in design. The notes of the cheng, like those of the concertina, speak either by inspiration or expiration of air, the former being the more usual method. Mahillon states that performers on the cheng in China are rare, as the method of playing by inspiration induces inflammation of the throat.[2] Amiot, who gives a description of the instrument with illustrations showing the construction, states that in the great Chinese encyclopaedia Eulh-ya, articles Yu and Ho, the Yu of ancient China was the large cheng with nineteen free reeds (twenty-four pipes), and the Ho the small cheng with thirteen reeds or seventeen pipes described in this article. The compass of the latter is given by him as the middle octave with chromatic intervals, the thirteenth note giving the octave of the first. Mahillon gives the compass of a modern cheng as follows:



E.F.F. Chladni,[3] who examined a cheng sent from China to Herr Muller, organist of the church of St Nicholas, Leipzig, at the beginning of the 19th century, gives an excellent description of the instrument, reproducing in illustration a plate from Giulio Ferrario's work on costume.[4] Muller's cheng had the same compass as Mahillon's. Chladni's article was motived by the publication of an account of the exhibition of G.J. Grenie's Orgue expressif, invented about 1810, in the Conservatoire of Paris.[5] Grenie's invention, perfected by Alexandre and Debain about 1840, produced the harmonium. Kratzenstein (see under HARMONIUM) of St Petersburg was the first to apply the free reed to the organ in the second half of the 18th century. Inventions of similar instruments, which after a short life were relegated to oblivion, followed at the beginning of the 19th century. An interesting reproduction of a Persian cheng dating from the 10th or 11th century is to be seen on a Persian vase described and illustrated together with a shawm in the Gazette archeologique (tome xi., 1886). (K. S.)

FOOTNOTES:

[1] Memoire sur la musique des Chinois (Paris, 1779), pp. 78 and 82, pl. vi., or Memoire sur les Chinois, tome vi. pl. vi.

[2] Catalogue descriptif, vol. ii. (Ghent, 1896), p. 91; also vol. i. (1880), pp. 29, 44, 154.

[3] "Weitere Nachrichten von dem ... chinesischen Blasinstrumente Tscheng oder Tschiang," in Allgemeine musikalische Zeitung (Leipzig, 1821), Bd. xxiii. No. 22, pp. 369, 374 et seq., and illustration appendix ii.

[4] Il Costume anticho e moderno (Milan, 1816), pl. 66, vol. i.

[5] See Allg. mus. Zt. (Leipzig, 1821), Bd. xxiii. Nos. 9 and 10, pp. 133 and 149 et seq.



CHEN-HAI [CHINHAI], a district town of China, in the province of Cheh-kiang, at the mouth of the Yung-kiang, 12 m. N.E. of Ningpo, in 29 deg. 58' N., 121 deg. 45' E. It lies at the foot of a hill on a tongue of land, and is partly protected from the sea on the N. by a dike about 3 m. long, composed entirely of large blocks of hewn granite. The walls are 20 ft. high and 3 m. in circumference. The defences were formerly of considerable strength, and included a well-built but now dismantled citadel on a precipitous cliff, 250 ft. high, at the extremity of the tongue of land on which the town is built. In the neighbourhood an engagement took place between the English and Chinese in 1841.



CHENIER, ANDRE DE (1762-1794), French poet, was born at Constantinople on the 30th of October 1762. His father, Louis Chenier, a native of Languedoc, after twenty years of successful commerce in the Levant as a cloth-merchant, was appointed to a position equivalent to that of French consul at Constantinople. His mother, Elisabeth Santi-Lomaca, whose sister was grandmother of A. Thiers, was a Greek. When the poet was three years old his father returned to France, and subsequently from 1768 to 1775 served as consul-general of France in Morocco. The family, of which Andre was the third son, and Marie-Joseph (see below) the fourth, remained in France; and after a few years, during which Andre ran wild with "la tante de Carcasonne," he distinguished himself as a verse-translator from the classics at the College de Navarre (the school in former days of Gerson and Bossuet) in Paris. In 1783 he obtained a cadetship in a French regiment at Strassburg. But the glamour of the military life was as soon exhausted by Chenier as it was by Coleridge. He returned to Paris before the end of the year, was well received by his family, and mixed in the cultivated circle which frequented the salon of his mother, among them Lebrun-Pindare, Lavoisier, Lesueur, Dorat, Parmy, and a little later the painter David. He was already a poet by predilection, an idyllist and steeped in the classical archaism of the time, when, in 1784, his taste for the antique was confirmed by a visit to Rome made in the company of two schoolfellows, the brothers Trudaine. From Naples, after visiting Pompeii, he returned to Paris, his mind fermenting with poetical images and projects, few of which he was destined to realize. For nearly three years, however, he was enabled to study and to experiment in verse without any active pressure or interruption from his family—three precious years in which the first phase of his art as a writer of idylls and bucolics, imitated to a large extent from Theocritus, Bion and the Greek anthologists, was elaborated. Among the poems written or at least sketched during this period were L'Oaristys, L'Aveugle, La Jeune Malade, Bacchus, Euphrosine and La Jeune Tarentine, the last a synthesis of his purest manner, mosaic though it is of reminiscences of at least a dozen classical poets. As in glyptic so in poetic art, the Hellenism of the time was decadent and Alexandrine rather than Attic of the best period. But Chenier is always far more than an imitator. La Jeune Tarentine is a work of personal emotion and inspiration. The colouring is that of classic mythology, but the spiritual element is as individual as that of any classical poem by Milton, Gray, Keats or Tennyson. Apart from his idylls and his elegies, Chenier also experimented from early youth in didactic and philosophic verse, and when he commenced his Hermes in 1783 his ambition was to condense the Encyclopedie of Diderot into a poem somewhat after the manner of Lucretius. This poem was to treat of man's position in the Universe, first in an isolated state, and then in society. It remains fragmentary, and though some of the fragments are fine, its attempt at scientific exposition approximates too closely to the manner of Erasmus Darwin to suit a modern ear. Another fragment called L'Invention sums Chenier's Ars Poetica in the verse "Sur des pensers nouveaux, faisons des vers antiques." Suzanne represents the torso of a Biblical poem on a very large scale, in six cantos.

In the meantime, Andre had published nothing, and some of these last pieces were in fact not yet written, when in November 1787 an opportunity of a fresh career presented itself. The new ambassador at the court of St James's, M. de la Luzerne, was connected in some way with the Chenier family, and he offered to take Andre with him as his secretary. The offer was too good to be refused, but the poet hated himself on the banks of the fiere Tamise, and wrote in bitter ridicule of

"Ces Anglais. Nation toute a vendre a qui peut la payer. De contree en contree allant au monde entier, Offrir sa joie ignoble et son faste grossier."

He seems to have been interested in the poetic diction of Milton and Thomson, and a few of his verses are remotely inspired by Shakespeare and Gray. To say, however, that he studied English literature would be an exaggeration. The events of 1789 and the startling success of his younger brother, Marie-Joseph, as political playwright and pamphleteer, concentrated all his thoughts upon France. In April 1790 he could stand London no longer, and once more joined his parents at Paris in the rue de Clery.

The France that he plunged into with such impetuosity was upon the verge of anarchy. A strong constitutionalist, Chenier took the view that the Revolution was already complete and that all that remained to be done was the inauguration of the reign of law. Moderate as were his views and disinterested as were his motives, his tactics were passionately and dangerously aggressive. From an idyllist and elegist we find him suddenly transformed into an unsparing master of poetical satire. His prose Avis au peuple francais (August 24, 1790) was followed by the rhetorical Jeu de paume, a somewhat declamatory moral ode addressed "a Louis David, peintre." In the meantime he orated at the Feuillants Club, and contributed frequently to the Journal de Paris from November 1791 to July 1792, when he wrote his scorching Iambes to Collot d'Herbois, Sur les Suisses revoltes du regiment de Chateauvieux. The 10th of August uprooted his party, his paper and his friends, and the management of relatives who kept him out of the way in Normandy alone saved him from the massacre of September. In the month following these events his democratic brother, Marie-Joseph, had entered the Convention. Andre's sombre rage against the course of events found vent in the line on the Maenads who mutilated the king's Swiss Guard, and in the Ode a Charlotte Corday congratulating France that "Un scelerat de moins rampe dans cette fange." At the express request of Malesherbes he furnished some arguments to the materials collected for the defence of the king. After the execution he sought a secluded retreat on the Plateau de Satory at Versailles and took exercise after nightfall. There he wrote the poems inspired by Fanny (Mme Laurent Lecoulteux), including the exquisite Ode a Versailles, one of his freshest, noblest and most varied poems.

His solitary life at Versailles lasted nearly a year. On the 7th of March 1794 he was taken at the house of Mme Piscatory at Passy. Two obscure agents of the committee of public safety were in search of a marquise who had flown, but an unknown stranger was found in the house and arrested on suspicion. This was Andre, who had come on a visit of sympathy. He was taken to the Luxembourg and afterwards to Saint-Lazare. During the 140 days of his imprisonment there he wrote the marvellous Iambes (in alternate lines of 12 and 8 syllables), which hiss and stab like poisoned bullets, and which were transmitted to his family by a venal gaoler. There he wrote the best known of all his verses, the pathetic Jeune captive, a poem at once of enchantment and of despair. Suffocating in an atmosphere of cruelty and baseness, Chenier's agony found expression almost to the last in these murderous Iambes which he launched against the Convention. Ten days before the end, the painter J.B. Suvee executed the well-known portrait. He might have been overlooked but for the well-meant, indignant officiousness of his father. Marie-Joseph had done his best to prevent this, but he could do nothing more. Robespierre, who was himself on the brink of the volcano, remembered the venomous sallies in the Journal de Paris. At sundown on the 25th of July 1794, the very day of his condemnation on a bogus charge of conspiracy, Andre Chenier was guillotined. The record of his last moments by La Touche is rather melodramatic and is certainly not above suspicion.

Incomplete as was his career—he was not quite thirty-two—his life was cut short in a crescendo of all its nobler elements. Exquisite as was already his susceptibility to beauty and his mastership of the rarest poetic material, we cannot doubt that Chenier was preparing for still higher flights of lyric passion and poetic intensity. Nothing that he had yet done could be said to compare in promise of assured greatness with the Iambes, the Odes and the Jeune Captive. At the moment he left practically nothing to tell the world of his transcendent genius, and his reputation has had to be retrieved from oblivion page by page, and almost poem by poem. During his lifetime only his Jeu de paume (1791) and Hymne sur les Suisses (1792) had been given to the world. The Jeune Captive appeared in the Decade philosophique, Jan. 9, 1795; La Jeune Tarentine in the Mercure of March 22, 1801. Chateaubriand quoted three or four passages in his Genie du christianisme. Fayette and Lefeuvre-Deumier also gave a few fragments; but it was not until 1819 that a first imperfect attempt was made by H. de la Touche to collect the poems in a substantive volume. Since the appearance of the editio princeps of Chenier's poems in La Touche's volume, many additional poems and fragments have been discovered, and an edition of the complete works of the poet, collated with the MSS. bequeathed to the Bibliotheque Nationale by Mme Elisa de Chenier in 1892, has been edited by Paul Dimoff and published by Delagrave. During the same period the critical estimates of the poet have fluctuated in a truly extraordinary manner. Sainte-Beuve in his Tableau of 1828 sang the praises of Chenier as an heroic forerunner of the Romantic movement and a precursor of Victor Hugo. Chenier, he said, had "inspired and determined" Romanticism. This suggestion of modernity in Chenier was echoed by a chorus of critics who worked the idea to death; in the meantime, the standard edition of Chenier's works was being prepared by M. Becq de Fouquieres and was issued in 1862, but rearranged and greatly improved by the editor in 1872. The same patient investigator gave his New Documents on Andre Chenier to the world in 1875.

In the second volume of La Vie litteraire Anatole France contests the theory of Sainte-Beuve. Far from being an initiator, he maintains that Chenier's poetry is the last expression of an expiring form of art. His matter and his form belong of right to the classic spirit of the 18th century. He is a contemporary, not of Hugo and Leconte de Lisle, but of Suard and Morellet. M. Faguet sums up on the side of M. France in his volume on the 18th century (1890). Chenier's real disciples, according to the latest view, are Leconte de Lisle and M. de Heredia, mosaistes who have at heart the cult of antique and pagan beauty, of "pure art" and of "objective poetry." Heredia himself reverted to the judgment of Sainte-Beuve to the effect that Chenier was the first to make modern verses, and he adds, "I do not know in the French language a more exquisite fragment than the three hundred verses of the Bucoliques." Chenier's influence has been specially remarkable in Russia, where Pushkin imitated him, Kogloff translated La Jeune Captive, La jeune Tarentine and other famous pieces, while the critic Vesselovsky pronounces "Il a retabli le lyrisme pur dans la poesie francaise." The general French verdict on his work is in the main well summed by Morillot, when he says that, judged by the usual tests of the Romantic movement of the 'twenties (love for strange literatures of the North, medievalism, novelties and experiments), Chenier would inevitably have been excluded from the cenacle of 1827. On the other hand, he exhibits a decided tendency to the world-ennui and melancholy which was one of the earlier symptoms of the movement, and he has experimented in French verse in a manner which would have led to his excommunication by the typical performers of the 18th century. What is universally admitted is that Chenier was a very great artist, who like Ronsard opened up sources of poetry in France which had long seemed dried up. In England it is easier to feel his attraction than that of some far greater reputations in French poetry, for, rhetorical though he nearly always is, he yet reveals something of that quality which to the Northern mind has always been of the very essence of poetry, that quality which made Sainte-Beuve say of him that he was the first great poet "personnel et reveur" in France since La Fontaine. His diction is still very artificial, the poetic diction of Delille transformed in the direction of Hugo, but not very much. On the other hand, his descriptive power in treating of nature shows far more art than the Trianin school ever attained. His love of the woodland and his political fervour often remind us of Shelley, and his delicate perception of Hellenic beauty, and the perfume of Greek legend, give us almost a foretaste of Keats. For these reasons, among others, Chenier, whose art is destined to so many vicissitudes of criticism in his own country, seems assured among English readers of a place among the Dii Majores of French poetry.

The Chenier literature of late years has become enormous. His fate has been commemorated in numerous plays, pictures and poems, notably in the fine epilogue of Sully Prudhomme, the Stello of A. de Vigny, the delicate statue by Puech in the Luxembourg, and the well-known portrait in the centre of the "Last Days of the Terror." The best editions are still those of Becq de Fouquieres (Paris, 1862, 1872 and 1881), though these are now supplemented by those of L. Moland (2 vols., 1889) and R. Guillard (2 vols., 1899). (T. SE.)



CHENIER, MARIE-JOSEPH BLAISE DE (1764-1811), French poet, dramatist and politician, younger brother of Andre de Chenier, was born at Constantinople on the 11th of February 1764.[1] He was brought up at Carcassonne, and educated in Paris at the College de Navarre. Entering the army at seventeen, he left it two years afterwards; and at nineteen he produced Azemire, a two-act drama (acted in 1786), and Edgar, ou le page suppose, a comedy (acted in 1785), which were failures. His Charles IX was kept back for nearly two years by the censor. Chenier attacked the censorship in three pamphlets, and the commotion aroused by the controversy raised keen interest in the piece. When it was at last produced on the 4th of November 1789, it achieved an immense success, due in part to its political suggestion, and in part to Talma's magnificent impersonation of Charles IX. Camille Desmoulins said that the piece had done more for the Revolution than the days of October, and a contemporary memoir-writer, the marquis de Ferriere, says that the audience came away "ivre de vengeance et tourmente d'une soif de sang." The performance was the occasion of a split among the actors of the Comedie Francaise, and the new theatre in the Palais Royal, established by the dissidents, was inaugurated with Henri VIII (1791), generally recognized as Chenier's masterpiece; Jean Calas, ou l'ecole des juges followed in the same year. In 1792 he produced his Caius Gracchus, which was even more revolutionary in tone than its predecessors. It was nevertheless proscribed in the next year at the instance of the Montagnard deputy Albitte, for an anti-anarchical hemistich (Des lois et non du sang!); Fenelon (1793) was suspended after a few representations; and in 1794 his Timoleon, set to Etienne Mehul's music, was also proscribed. This piece was played after the fall of the Terror, but the fratricide of Timoleon became the text for insinuations to the effect that by his silence Joseph de Chenier had connived at the judicial murder of Andre, whom Joseph's enemies alluded to as Abel. There is absolutely nothing to support the calumny, which has often been repeated since. In fact, after some fruitless attempts to save his brother, variously related by his biographers, Joseph became aware that Andre's only chance of safety lay in being forgotten by the authorities, and that ill-advised intervention would only hasten the end. Joseph Chenier had been a member of the Convention and of the Council of Five Hundred, and had voted for the death of Louis XVI.; he had a seat in the tribunate; he belonged to the committees of public instruction, of general security, and of public safety. He was, nevertheless, suspected of moderate sentiments, and before the end of the Terror had become a marked man. His purely political career ended in 1802, when he was eliminated with others from the tribunate for his opposition to Napoleon. In 1801 he was one of the educational jury for the Seine; from 1803 to 1806 he was inspector-general of public instruction. He had allowed himself to be reconciled with Napoleon's government, and Cyrus, represented in 1804, was written in his honour, but he was temporarily disgraced in 1806 for his Epitre a Voltaire. In 1806 and 1807 he delivered a course of lectures at the Athenee on the language and literature of France from the earliest years; and in 1808 at the emperor's request, he prepared his Tableau historique de l'etat et du progres de la litterature francaise depuis 1789 jusqu'a 1808, a book containing some good criticism, though marred by the violent prejudices of its author. He died on the 10th of January 1811. The list of his works includes hymns and national songs—among others, the famous Chant du depart; odes, Sur la mort de Mirabeau, Sur l'oligarchie de Robespierre, &c.; tragedies which never reached the stage, Brutus et Cassius, Philippe deux, Tibere; translations from Sophocles and Lessing, from Gray and Horace, from Tacitus and Aristotle; with elegies, dithyrambics and Ossianic rhapsodies. As a satirist he possessed great merit, though he sins from an excess of severity, and is sometimes malignant and unjust. He is the chief tragic poet of the revolutionary period, and as Camille Desmoulins expressed it, he decorated Melpomene with the tricolour cockade.

See the Oeuvres completes de Joseph Chenier (8 vols., Paris, 1823-1826), containing notices of the poet by Arnault and Daunou; Charles Labitte, Etudes litteraires (1846); Henri Welschinger, Le Theatre revolutionnaire, 1789-1799 (1881); and A. Lieby, Etude sur le theatre de Marie-Joseph Chenier(1902).

FOOTNOTE:

[1] This is the date given by G. de Chenier in his La Verite sur la famille de Chenier (1844).



CHENILLE (from the Fr. chenille, a hairy caterpillar), a twisted velvet cord, woven so that the short outer threads stand out at right angles to the central cord, thus giving a resemblance to a caterpillar. Chenille is used as a trimming for dress and furniture.



CHENONCEAUX, a village of central France, in the department of Indre-et-Loire, on the right bank of the Cher, 20 m. E. by S. of Tours on the Orleans railway. Pop. (1906) 216. Chenonceaux owes its interest to its chateau (see ARCHITECTURE: Renaissance Architecture in France), a building in the Renaissance style on the river Cher, to the left bank of which it is united by a two-storeyed gallery built upon five arches, and to the right by a drawbridge flanked by an isolated tower, part of an earlier building of the 15th century. Founded in 1515 by Thomas Bohier (d. 1523), financial minister in Normandy, the chateau was confiscated by Francis I. in 1535. Henry II. presented it to his mistress Diane de Poitiers, who on his death was forced to exchange it for Chaumont-sur-Loire by Catherine de' Medici. The latter built the gallery which leads to the left bank of the Cher. Chenonceaux passed successively into the hands of Louise de Vaudemont, wife of Henry III., the house of Vendome, and the family of Bourbon-Conde. In the 18th century it came into the possession of the farmer-general Claude Dupin (1684-1769), who entertained the most distinguished people in France within its walls. In 1864 it was sold to the chemist Theophile Pelouze, whose wife executed extensive restorations. It subsequently became the property of the Credit Foncier, and again passed into private occupancy.



CHENOPODIUM, or GOOSE-FOOT, a genus of erect or prostrate herbs (natural order Chenopodiaceae), usually growing on the seashore or on waste or cultivated ground. The green angular stem is often striped with white or red, and, like the leaves, often more or less covered with mealy hairs. The leaves are entire, lobed or toothed, often more or less deltoid or triangular in shape. The minute flowers are bisexual, and borne in dense axillary or terminal clusters or spikes. The fruit is a membranous one-seeded utricle often enclosed by the persistent calyx. Ten species occur in Britain, one of which, C. Bonus-Henricus, Good King Henry, is cultivated as a pot-herb, in lieu of asparagus, under the name mercury, and all-good.



CHEOPS, in Herodotus, the name of the king who built the Great Pyramid in Egypt. Following on a period of good rule and prosperity under Rhampsinitus, Cheops closed the temples, abolished the sacrifices and made all the Egyptians labour for his monument, working in relays of 100,000 men every three months (see PYRAMID). Proceeding from bad to worse, he sacrificed the honour of his daughter in order to obtain the money to complete his pyramid; and the princess built herself besides a small pyramid of the stones given to her by her lovers. Cheops reigned 50 years and was succeeded by his brother, Chephren, who reigned 56 years and built the second pyramid. During these two reigns the Egyptians suffered every kind of misery and the temples remained closed. Herodotus continues that in his own day the Egyptians were unwilling to name these oppressors and preferred to call the pyramids after a shepherd named Philition, who pastured his flocks in their neighbourhood. At length Mycerinus, son of Cheops and successor of Chephren, reopened the temples and, although he built the Third Pyramid, allowed the oppressed people to return to their proper occupations.

Cheops, Chephren and Mycerinus are historical personages of the fourth Egyptian dynasty, in correct order, and they built the three pyramids attributed to them here. But they are wholly misplaced by Herodotus. Rhampsinitus, the predecessor of Cheops, appears to represent Rameses III. of the twentieth dynasty, and Mycerinus in Herodotus is but a few generations before Psammetichus, the founder of the twenty-sixth dynasty. Manetho correctly places the great Pyramid kings in Dynasty IV. In Egyptian the name of Cheops (Chemmis or Chembis in Diodorus Siculus, Suphis in Manetho) is spelt Hwfw (Khufu), but the pronunciation, in late times perhaps Khoouf, is uncertain. The Greeks and Romans generally accepted the view that Herodotus supplies of his character, and moralized on the uselessness of his stupendous work; but there is nothing else to prove that the Egyptians themselves execrated his memory. Modern writers rather dwell on the perfect organization demanded by his scheme, the training of a nation to combined labour, the level attained here by art and in the fitting of masonry, and finally the fact that the Great Pyramid was the oldest of the seven wonders of the ancient world and now alone of them survives. It seems that representations of deities, and indeed any representations at all, were rare upon the polished walls of the great monuments of the fourth dynasty, and Petrie thinks that he can trace a violent religious revolution with confiscation of endowments at this time in the temple remains at Abydos; but none the less the wants of the deities were then attended to by priests selected from the royal family and the highest in the land. Khufu's work in the temple of Bubastis is proved by a surviving fragment, and he is figured slaying his enemy at Sinai before the god Thoth. In late times the priests of Denderah claimed Khufu as a benefactor; he was reputed to have built temples to the gods near the Great Pyramids and Sphinx (where also a pyramid of his daughter Hentsen is spoken of), and there are incidental notices of him in the medical and religious literature. The funerary cult of Khufu and Khafrē was practised under the twenty-sixth dynasty, when so much that had fallen into disuse and been forgotten was revived. Khufu is a leading figure in an ancient Egyptian story (Papyrus Westcar), but it is unfortunately incomplete. He was the founder of the fourth dynasty, and was probably born in Middle Egypt near Beni Hasan, in a town afterwards known as "Khufu's Nurse," but was connected with the Memphite third dynasty. Two tablets at the mines of Wadi Maghara in the peninsula of Sinai, a granite block from Bubastis, and a beautiful ivory statuette found by Petrie in the temple at Abydos, are almost all that can be definitely assigned to Khufu outside the pyramid at Giza and its ruined accompaniments. His date, according to Petrie, is 3969-3908 B.C., but in the shorter chronology of Meyer, Breasted and others he reigned (23 years) about a thousand years later, c. 2900 B.C.

See Herodotus ii. 124; Diodorus Siculus i. 64; Sethe in Pauly-Wissowa's Realencyclopadie, s.v.; W.M.F. Petrie, History of Egypt, vol. i., and Abydos, part ii. p. 48; J.H. Breasted, History. (F. LL. G.)



CHEPSTOW, a market town and river-port in the southern parliamentary division of Monmouthshire, England, on the Wye, 2 m. above its junction with the Severn, and on the Great Western railway. Pop. of urban district (1901) 3067. It occupies the slope of a hill on the western (left) bank of the river, and is environed by beautiful scenery. The church of St Mary, originally the conventual chapel of a Benedictine priory of Norman foundation, has remains of that period in the west front and the nave, but a rebuilding of the chancel and transepts was effected in the beginning of the 19th century. The church contains many interesting monuments. The castle, still a magnificent pile, was founded in the 11th century by William Fitz-Osbern, earl of Hereford, but was almost wholly rebuilt in the 13th. There are, however, parts of the original building in the keep. The castle occupies a splendid site on the summit of a cliff above the Wye, and covers about 3 acres. The river is crossed by a fine iron bridge of five arches, erected in 1816, and by a tubular railway bridge designed by Sir Isambard Brunel. There is a free passage on the Wye for large vessels as far as the bridge. From the narrowness and depth of the channel the tide rises suddenly and to a great height, forming a dangerous bore. The exports are timber, bark, iron, coal, cider and millstones. Some shipbuilding is carried on.

As the key to the passage of the Wye, Chepstow (Estrighorel, Striguil) was the site successively of British, Roman and Saxon fortifications. Domesday Book records that the Norman castle was built by William Fitz-Osbern to defend the Roman road into South Wales. On the confiscation of his son's estates, the castle was granted to the earls of Pembroke, and after its reversion to the crown in 1306, Edward II. in 1310 granted it to his half-brother Thomas de Brotherton. On the latter's death it passed, through his daughter Margaret, Lady Segrave, to the dukes of Norfolk, from whom, after again reverting to the crown, it passed to the earls of Worcester. It was confiscated by parliament and settled on Oliver Cromwell, but was restored to the earls in 1660. The borough must have grown up between 1310, when the castle and vill were granted to Thomas de Brotherton, and 1432, when John duke of Norfolk died seised of the castle, manor and borough of Struguil. In 1524 Charles, first earl of Worcester and then lord of the Marches, granted a new charter of incorporation to the bailiffs and burgesses of the town, which had fallen into decay. This was sustained until the reign of Charles II., when, some dispute arising between the earl of Bridgwater and the burgesses, no bailiff was appointed and the charter lapsed. Chepstow was afterwards governed by a board of twelve members. A port since early times, when the lord took dues of ships going up to the forest of Dean, Chepstow had no ancient market and no manufactures but that of glass, which was carried on for a short time within the ruins of the castle.